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Parborlasia corrugatus McIntosh is a large, abundant, epibenthic antarctic nemertean which represents a considerable source of nutrition for predators. The energetic composition of adult body tissues (kJ·g -1 dry wt) is comprised primarily of energy derived from protein (11.4 kJ NaOH-insoluble, 6 kJ NaOH-soluble). Energy units associated with lipid (4.3 kJ) and carbohydrate (0.2 kJ) are much lower. Based on calculations of the energetic composition of whole body tissues, and a density of 0.3 ind·m -2, mean population energetic density is estimated to be 65 kJ·m -2. These values are often significantly higher as P. corrugatus aggregates when feeding. Despite their high abundance, nemerteans are not preyed upon and appear to be chemically defended. Sperm of the antarctic sea urchin Sterechinus neumeyeri (Meissner) were killed when exposed to a 3% aqueous extract of whole nemertean body tissues. In laboratory feeding experiments, two common species of antarctic fish showed significant rejection of nemerteans. Its toxic and feeding-deterrent characteristics are probably the result of the epithelial production of copious acidic mucus (pH = 3.5), although other toxic or noxious metabolites may be present. These results indicate that P. corrugatus, an important scavenger in antarctic benthic systems, is abundant, high in nutrients and energy content, and could be judged on this basis as a high-quality prey item. Nonetheless, due to its chemical defense, potential predators may avoid ingestion of this species., Cited By (since 1996):28, Invertebrates,
Antarctica, CODEN: JEMBA, ,

Information on the diet of the Marbled Murrelet, Brachyramphus marmoratus, in California is lacking. To assess availability of potential prey, we sampled small fishes at three locations in central California: Año Nuevo Bay, and two sites in northern Monterey Bay. These sites are used seasonally by Marbled Murrelets. Nearshore marine habitats were sampled with a midwater trawl during 2000, 2001, and 2002. We caught 36 taxa of demersal and midwater fish and cephalopods. Numerically dominant species at all sites were northern anchovy, Engraulis mordax, night smelt, Spirinchus starski, and white croaker, Genyonomus lineatus. The occurrence of these fishes concurrent with Marbled Murrelets provides information on potential prey available to Marbled Murrelets in central California., Cited By (since 1996):3

Scientific information is often interpreted to the public long after it has been discovered. NOAA programs and private organizations are interested in more immediate sharing of information with the public so that it can be more effectively used in resource management. The Davidson Seamount is an underwater volcano off the coast of Central California, and recent advances in technology provide the opportunity to explore and characterize the biology of this deep-sea habitat. With an interdisciplinary team of scientists, outreach specialists, and resource managers, this exploration was presented to the public as it was happening with daily updates on a web site. The public also interacted by e-mail with the explorers during the expedition. Huge corals and sponges, deep-water fishes, and the technology needed to study this deep, dark habitat particularly engaged the public, resource managers, and scientists alike. Following the cruise there was national media interest in discoveries from the expedition, not only because the findings were spectacular, but because significant efforts were made to provide the media with access to the explorers and images of the findings. Resource managers are already using summary information from the cruise in processes that may potentially protect Davidson Seamount habitats. Even before the scientific data has been completely analyzed, the public and resource managers have been engaged in a healthy process of information sharing. In characterizing the biology of Davidson Seamount, we found that this model of an interdisciplinary expedition effectively integrated new scientific information into public understanding and management options for a unique area., , ,

Cited By (since 1996):19
Seaweeds, CODEN: MESED, In March 1989, the 'Exxon Valdez' spilled over 10 million gallons (ca 38 million I) of crude
oil into Prince William Sound, Alaska , USA. The spill was followed by massive clean-up using hot seawater
at high pressure as well as other mechanical and chemical techniques. We studied initial damage
and subsequent recovery in the upper margin of the Fucus gardneri assemblage on protected shores by
comparing sites that were unoiled, oiled and cleaned with hot water at high pressure, and oiled but less
intensely cleaned. F. gardneri cover averaged 80% on unoiled sites but< 1 % on all oiled and cleaned
sites 18 mo after the spill. The abundances of barnacles, littorine snails and limpets varied among sites
and species, and this variation was associated in part with differences in their life histories. F. gardneri
cover was still extremely low on oiled and cleaned sites 2.5 yr after the spill. Holdfasts that persisted
after cleaning did not resprout. F. gardneri recruitment was lowest at intensely cleaned sites, and most
recruits occurred in cracks near adults. Recruits were less abundant under adult canopies but placing
canopies over recruits did not decrease their survivorship over 5 mo. Natural weathering of tar was
rapid, with most marked patches gone in less than 1 yr. We conclude that intense mechanical cleaning
following this oil spill increased damage and slowed recovery. Such methods should be avoided if
reduction of environmental damage is the primary objective of post-spill management decisions. The
recovery of F. gardneri at its upper margin might be enhanced by devices that retain moisture and
increase substratum rugosity., ,

Techniques for enhancing vertebral bands in age estimation of California elasmobranchs

Description

Vertebrae from 1,152 elasmobranchs representing 22 species were collected between 1979 and 1981 to assess methods of enhancing incremental growth bands for age estimation. Thus far, we have tested methods previouslyreported in the literature, and have developed new procedures to enhance growth increments on 684 individuals of 14 species of elasmobranchs. Silver nitrate impregnation, X-radiograpby, and cedarwood oil clearing were the most successful techniques. Less effeetive were alizarin red staining, paraffin impregnation, alcohol immersiorn, and formic acid etching. Methods for preparing vertebrae and enhancing and counting growth increments are presented, and the problems associated with interpreting tile annual nature of such counts are discussed.

In recent years, population declines related to viral outbreaks in marine mammals have been associated with polluted coastal waters and high tissue concentrations of certain persistent, lipophilic contaminants. Such observations suggest a contributing role of contaminant-induced suppression of cell-mediated immunity leading to decreased host resistance. Here, we assessed the effects of the prototypic polycyclic aromatic hydrocarbon (PAH), benzo[a]pyrene (B[a]P), and two polychlorinated biphenyls (PCBs), CB-156 and CB-80, on the T-cell proliferative response to mitogen in harbor seal peripheral lymphocytes. Despite the variability associated with our samples from free-ranging harbor seals, we observed a clear suppressive effect of B[a]P (10 uM) exposure on T cell mitogenesis. Exposures to 10 uM CB-156 and CB-80, and 1.0 and 0.1 uM B[a]P, did not produce significant depression in lymphoproliferation. Exposure to the model PAH at 10 uM resulted in a 61% (range 34-97%) average reduction in lymphoproliferation. We were able to rule out a direct cytotoxic effect of B[a]P, indicating that observed effects were due to altered T cell function. Based on our in vitro results, we hypothesize that extensive accumulation of PAH by top-trophic-level marine mammals could alter T cell activation in vivo and impaired cell-mediated immunity against viral pathogens., Cited By (since 1996):12, CODEN: DEIME, ,

Abundance, seasonal distribution and population composition of balaenopterid whales in the Canal de Ballenas, Gulf of California, Mexico,

Description

Blue whales Balaenoptera musculus were most abundant in April and May while minke B. acutorostrata whales were equally abundant throughout the year. Fin B. physalus and Bryde's whales B. edeni were found but fin whales were more abundant in winter and spring; numbers were negatively correlated with water temperature. Bryde's whales were more abundant in summer and fall; numbers were positively correlated with water temperature. The percentage of identified individual adults that were females with calves was 10.6 for Bryde's and 2.7 for fin whales., Cited By (since 1996):13, , , Marine Mammals, Birds & Turtles

A review of apparent 20th century changes in the presence of mussels (Mytilus trossulus) and macroalgae in Arctic, Alaska, and of historical and paleontological evidence used to relate mollusc distributions to climate change

Description

Live mussels attached to fresh laminarioid brown algae, all fastened to clusters of pebbles and small cobbles, were repeatedly cast ashore by autumn storms at Barrow, Alaska, in the 1990s. Specimens of Laminaria saccharina and L. solidungula shorten by 100 km a 500 km gap (Peard Bay to Stefansson Sound) between previously known concentrations of these kelp species. For the genus Mytilus, a 1 600 km gap in fully documented locations existed between Kivalina in the southern Chukchi Sea and the Mackenzie River delta. Barrow specimens were identified using a mitochondrial DNA marker as M. trossulus, an identity consistent with dispersal from the Pacific-Bering side of the Arctic. Live mussels and macroalgae were neither washed up by storms nor collected by active biological sampling during extensive benthic surveys at Barrow in 1948-50. We cannot interpret the current presence of these bivalves and macrophytes as Arctic range extensions due to warming, similar to those manifested by the tree line in terrestrial systems and by Pacific salmon in marine environments. Supplemental information and critical evaluation of survey strategies and rationales indicate that changes in sea temperatures are an unlikely cause. Alternative explanations focus on past seafloor disturbances, dispersal from marine or estuarine refugia, and effects of predators on colonists. This review suggests refining some interpretations of environmental change that are based on the extensive resource of Cenozoic fossils of Arctic molluscs., Cited By (since 1996):16, CODEN: ATICA, Invertebrates

Benthic manganese fluxes along the Oregon-California continental shelf and slope

Description

Here we examine the factors that influence the manganese (Mn) benthic flux from eastern North Pacific marine sediments, with a primary emphasis on continental shelf locations off Oregon and California and studies that involve the use of in situ benthic chambers. Typical shelf-to-shallow margin (

, , , Fluxes of lead to the Great Lakes are dominated by atmospheric depositions of industrial lead, which account for ~ 64% of the lead inputs to Lake Ontario and >90% of the inputs to Lake Superior. It has recently been demonstrated that lead aerosols in the Great Lakes region may be identified by the contrasting 206Pb/207Pb ratios of industrial leads from the United States (1.221 ±0.009) and Canada (1.151 ±0.010). Here we show that those ratios may also be used to identify and trace industrial lead inputs to the Great Lakes. These corroborate spatial gradients in lead concentrations in surface waters, which range from 290 pmol kg−1 in Hamilton Harbour to <10 pmol kg−1 in the central waters of Lake Ontario. The latter concentrations and corresponding residence-time estimates, which are both an order of magnitude lower than previously reported, indicate that lead is rapidly scavenged in the epilimnion during periods of high primary productivity. We find that industrial lead from Canada and the United States are the two principal sources of lead contamination in the Great Lakes., ,

Particle size statistics (coarsest 1 percentile and mean) of the nonbiogenic silt fraction of samples from Deep Sea Drilling Project sites 514, 516A, 517, 518, and 548 were used to infer relative changes in paleospeed of deep water masses in the Atlantic Ocean during the late Pliocene initiation of northern hemisphere glaciation. Grain size statistics were integrated with previous studies of geochemical and faunal assemblages to examine how climatic forcing regulates deepwater mass paleospeed and stratification. On the basis of between-site comparison of particle size, the late Pliocene was divided into four intervals of deepwater activity: 3.2 to 2.9 Ma, 2.9 to 2.6 Ma, 2.6 to 2.5 Ma, and 2.5 to 2.3 Ma, with pulses of increased paleospeed occurring at 3.15-3.10, 2.85, 2.7, 2.6 and 2.4 Ma., Cited By (since 1996):8
Rocks and Cores, ,

Numerous small (9 ± 7 m2, mean ± SD) depressions filled with dark water were found covering 14% of the shallows (<10 m) sea floor of Resolute Bay, NWT, Canada, on July 28, 1995. The water in these black pools was hypoxic, warmer, and more saline and sulfide rich than surrounding bottom water. These pools also contained high numbers of dead epibenthic species, including: shrimps, amphipods, mysids, bivalves, gastropods, sea cucumbers, and fishes. Infaunal abundance and biomass, as well as benthic chlorophyll concentrations, were significantly lower inside the black pools than in the surrounding sediments. The pools persisted until the first strong wind to occur after annual sea-ice break-up. A year (July 1996), sulfide-rich black saline pools were again found in the same depressions as well as in new depressions formed by grounding ice during the previous summer. We hypothesize that the pools form annually, as the sea ice expels dense brine, which sinks and collects in previously formed ice gouge depressions on the shallow of Resolute Bay. Benthic respiration would be sufficient to drive the stratified water in the pools to anoxia in the absence of currents and turnover, resulting in microbial production of highly toxic sulfides. Once established, the pools persist as lethal traps for benthic and demersal organisms until dispersed by wind or waves after breakup of the annual ice cover., Cited By (since 1996):27,
Invertebrates, CODEN: MESED, ,

Resource use by five sympatric parrotfishes in the San Blas Archipelago, Panama,

Description

Resource use by five sympatric species of parrotfish was quantified in the San Blas Archipelago of the Republic of Panama from March to August 1987. Detailed observations of parrotfishes on patch reefs and surrounding seagrass beds showed that they partition resources with respect to habitat, food and size, but not time. Although parrotfishes shared resources, the proportions of each resource used differed significantly among species. Scarus iserti (Bloch) scraped filamentous microalgae that grew from eroded coral pavement on lower slopes of patch reefs and in 'halos,' the area of sparse vegetation surrounding reefs. Sparisoma viride (Bonnaterre) foraged on upper slopes of patch reefs where they mostly took bites from dead coral and associated algae. S. aurofrenatum (Cuvier and Valenciennes) had the broadest diet, which consisted mostly of seagrasses and macro- and microalgae that were attached to dead coral on lower reef slopes and in halos. Although S. chrysopterum (Bloch and Schneider) commonly occurred on patch reefs, it primarily foraged in seagrass beds that surround them. S. rubripinne (Cuvier and Valenciennes) was distributed most widely, ranging from seagrass beds to reef crests, where it took bites from seagrasses, dead coral and macroalgae. Juveniles of all species occurred on lower slopes or in halos where they scraped filamentous microalgae from coral pavement. As they matured, parrotfishes moved into other habitats changing access to different types of food. All of these parrotfishes fed throughout the daytime, and resource use did not differ between morning and afternoon., Cited By (since 1996):45, CODEN: MBIOA, ,

Cold seep communities discovered at three previously unknown sites between 600 and 1000 m in Monterey Bay, California, are dominated by chemoautotrophic bacteria (Beggiatoa sp.) and vesicomyid clams (5 sp.). Other seep-associated fauna included galatheid crabs (Munidopsis sp.), vestimentiferan worms (Lamellibrachia barhami?), solemyid clams (Solemya sp.), columbellid snails (Mitrella permodesta, Amphissa sp.), and pyropeltid limpets (Pyropelta sp.). More than 50 species of regional (i.e. non-seep) benthic fauna were also observed at seeps. Ratios of stable carbon isotopes (δ13C) in clam tissues near -36‰ indicate sulfur-oxidizing chemosynthetic production, rather than non-seep food sources, as their principal trophic pathway. The 'Mt Crushmore' cold seep site is located in a vertically faulted and fractured region of the Pliocene Purisima Formation along the walls of Monterey Canyon (~635 m), where seepage appears to derive from sulfide-rich fluids within the Purisima Formation. The 'Clam Field' cold seep site, also in Monterey Canyon (~900 m) is located near outcrops in the hydrocarbon-bearing Monterey Formation. Chemosynthetic communities were also found at an accretionary-like prism on the continental slope near 1000 m depth (Clam Flat site). Fluid flow at the 'Clam Flat' site is thought to represent dewatering of accretionary sediments by tectonic compression, or hydrocarbon formation at depth, or both. Sulfide levels in pore waters were low at Mt Crushmore (ca 0.2 mM), and high at the two deeper sites (ca 7.011.0 mM). Methane was not detected at the Mt Crushmore site, but ranged from 0.06 to 2.0 mM at the other sites., Cited By (since 1996):108,
Invertebrates, CODEN: DRORE, ,